gleff: You raise a good point. To address your question about benefits:

All I can say is that the ratings gives people some semblance of what other FlyerTalkers feel about a thread. As I stated in my post above, one must be careful not to read too deeply into statistics. Indeed, the meaning of individual votes which comprise the overall rating is open to interpretation and should not be the subject of speculation, as there are simply too many factors that enter into consideration when one chooses their thread rating. Likewise, the meaning of the aggregated average rating is open to interpretation too! One can choose not to pay much heed to the rating (as what dhammer said above -- a high rating isn't necessarily going to motivate him to open a thread he wouldn't have already) or it might have some small (and I emphasise small) effect on whether people open a thread.

Each person gets one vote (and cannot change their votes, in the default vBulletin settings), but no one has to vote either. If I put enough meaning into thread ratings that I actually dislike the fact that the displayed rating of a thread does not reflect what I think about it, then I can either ignore the rating, or vote the number of stars which reflects what I think it should be. If I'm only one of 10 or 15 or 20 voters, then the "power" of my vote alone on the average rating is minimal.

I think the harm that has come from the system in its initial implementation was came from two things:
1) that the ratings were displayed with just two votes (that's the default setting), which is completely statistically insignificant;
2) that people were reading too much into what individual votes meant.

I think to a large degree that the latter followed from the former. If we address the former, by increasing the setting, then the second problem also goes away.

FewMiles..